The "Save As Webpage" option no longer exists on PowerPoint 2010 and later.

Microsoft has provided a workaround, summarized as, "use the ppSaveAsHTML argument for the *.htm file format."

• In PowerPoint 2010, open the presentation that you want to export to HTML.
• Press Alt+F11, this opens VB for Apps.
• Press Ctrl+G, this opens the Immediate pane.

• In the Immediate pane, type the following, and then press the Enter key:

  

  

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  ActivePresentation.SaveAs "<Drive>:\users\<username>\desktop\<filename>.htm", ppSaveAsHTML, msoFalse

To save by using the Single File Web Page (*.mht;*.mhtml) file format, replace htm at the end of the file name with mht, and replace ppSaveAsHTML with ppSaveAsWebArchive.

[출처] https://stackoverflow.com/questions/6274218/how-to-convert-from-powerpoint-to-html-css-foss